The chemical formula would dictate how many ions are present in a solution. It tells how many of what ion would dissociate in the solution. In every chemical reaction or dissociation reaction, it is important to remember that the number of each atoms on each side would be equal.
Since there are only 2 significant figures in 0.024 ( and 0.024 is the number with the least number of significant numbers), the answer is 330,000, not 331,000.
